[IT IS USEFULL THE UREA/CREATININE RATE FORDIFFERENTIATION OF UPPER FROM LOWER GASTROINTESTINAL BLEEDING?]

Gastrointestinal bleeding constitutes a third part of the hospitalizations in our service. Some times is difficult to clinically distinguish the site of bleeding. It was pointed that the urea/creatinine ratio can help to define the site of bleeding, but there is a lot of superposition in the results. We studied prospectively 154 patients with gastrointestinal bleeding. 123 (79.9%) patients had upper gastrointestinal bleeding with an urea/creatinine ratio of 62.27 +/- 29.13 and 31(20.1%) patients had lower gastrointestinal bleeding with an urea/creatinine ratio of 39.49 +/- 13.83. This difference is statistically significant but has a lot of overlap results. Defining gastrointestinal bleeding as an urea/creatinine ratio greater than 60, we found a great specificity (96.77%) but a low sensibility (51.22). In addition, when we only took hematochezia cases, that usually is a diagnostic problem, the specificity was 96.42% and the sensitivity 46.15%. In conclusion, an urea/creatinine ratio greater than 60 usually indicate us an upper gastrointestinal bleeding, but values below of 60 isn't of diagnostic value.